The present invention relates to the field of manufacturing packaging bags.
More precisely, the present invention relates to apparatuses for manufacturing packaging bags from a continuously traveling film fitted with at least one tape having an opening/closing function. More precisely still, the present invention relates preferably to apparatuses for manufacturing bags in which the tape having an opening/closing function extends transversely to the travel direction of the film.
Nevertheless, as described in greater detail below, the present invention is not limited to this specific application. The invention can also be applied to apparatuses in which said tapes having an opening/closing function are disposed parallel to the travel direction of the film or obliquely relative to said direction.
Numerous apparatuses of this kind are known.
The tape having an opening/closing function can take numerous forms.
By way of example, the tape having an opening/closing function can be formed by complementary closure strips, e.g. male/female strips, or strips with complementary hooks, placed on opposite faces of the film.
The tape having an opening/closing function can also be formed by a tear/cut tape or strip, an adhesive tape, which can optionally be a peel-off tape, or indeed a metal tape for closing by being folded, etc.
Such apparatuses for manufacturing packaging bags are known in which travel takes place horizontally or vertically.
In particular, so-called form, fill, and seal (FFS) machines are known which automatically form the bags, fill them, and then close them.
In particular, FFS machines are known that comprise:                means for delivering the film in the plane state;        means for shaping the film into a tubular state on a forming neck;        means for closing the resulting tube longitudinally, generally by heat-sealing;        a funnel which opens out into the tube formed in this way for conveying the product that is to be packaged; and        means for fixing the tubular film in a transverse direction, generally again by heat-sealing.        
Still more precisely, said means are generally designed to provide almost simultaneously a line of heat-sealing that constitutes, for example, the bottom of a bag that is upstream in the travel direction, a second line of heat-sealing closing the mouth of a bag downstream therefrom, and a line of cut sectioning the tubular film so as to separate the finished downstream bag from the upstream bag that is in preparation.
In particular, machines now exist that have a station designed for fixing the tape having an opening/closing function onto the film upstream from the forming neck, and to do so transversely relative to the travel direction of the film.
Nevertheless, in a variant, the closure tape can be placed longitudinally, i.e. parallel to the travel direction of the film, or indeed obliquely relative to said direction.
Those known machines have already given good service.
Nevertheless, they do not always give complete satisfaction in the sense that it is sometimes difficult to control accurately proper positioning of the tape having an opening/closing function.
This problem is particularly severe with machines that operate continuously with the film travelling at very high speed.